Modelling a sphere with 2 flat faces
To make a sphere with flat faces:


Put your picture as Background Image.
Create a cube and W > Subdivide Smooth.
Cut it with the knife tool (K to activate, Z to cut through, C to cut perpendicularly).
Use V to separate the pieces you want to delete, then delete.
Clean a bit the rim with some merge (alt M).
Extrude to create faces, merge at center.
Give it a Subdivision Surface modifier and click Shading > Smooth to smooth.




I've tried a more detailed version, with the button holes etc... In that case a UV Sphere seems better to begin:


Put your picture as Background Image.
Create a UV Sphere (48 segments, 24 rings), keep a copy on another layer, give this copy a Subsurf modifier.
Rotate your original sphere 45°. Give it a Shrinkwrap modifier with the copy as Target so that the shape of the original will stick to a sphere shape during the next operations.
Cut the top of your sphere, align the rim to the picture’s rim.
Cut 2 holes on the side, extrude and scale to create 2 circles for the buttons (use W > LoopsTools > Circle, or shift alt S).
Cut the base with the knife tool (K to activate, Z to cut through, C to cut perpendicularly).
Apply the Shrinkwrap modifier.
Make some extrudes for all these holes.
For the sphere's « equator » make a thin bevel and extrude .
Etc…